Relation of apolipoprotein (a) phenotypes to diabetic retinopathy in elderly type 2 diabetes

Low-molecular-weight lipoprotein (a) and low relative lymphocyte concentration are significant and independent risk factors for coronary heart disease in patients with type 2 diabetes mellitus: Lp(a) phenotype, lymphocyte, and coronary heart disease

Background

The aim of the present prospective study was to examine whether lipoprotein (a) [Lp(a)] phenotypes and/or low relative lymphocyte concentration (LRLC) are independently associated with coronary heart disease (CHD) in patients with type 2 diabetes mellitus (T2DM).

Methods

Serum Lp(a) concentration, Lp(a) phenotypes, and RLC were analyzed in 214 subjects. Lp(a) phenotypes were classified into 7 subtypes according to sodium dodecyl sulfate-agarose gel electrophoresis by Western blotting. Subjects were assigned to the low-molecular-weight (LMW (number of KIV repeats: 11–22) ) and high-molecular-weight (HMW( number of KIV repeats: >22 )) Lp(a) groups according to Lp(a) phenotype and to the LRLC (RLC: <20.3%) and normal RLC (NRLC; RLC: ≥20.3%) groups according to RLC. A CHD event was defined as the occurrence of angina pectoris or myocardial infarction during the follow-up period.

Results

During the follow-up period, 30 cases of CHD events were verified. Neutrophil count showed no correlation with CHD, while relative neutrophil concentration and RLC showed positive and negative correlations, respectively, with CHD. The Cox proportional hazard model analysis revealed the following hazard ratios adjusted for LMW Lp(a), LRLC, and LMW Lp(a) + LRLC: (4.31; 95% confidence interval [CI], 1.99-9.32; P < 0.01, 3.621; 95% CI, 1.50-8.75; P < 0.05, and 7.15; 95% CI, 2.17-23.56; P < 0.01, respectively).

Conclusions

Our results suggest that both LMW Lp(a) and LRLC are significant and independent risk factors for CHD and that the combination thereof more strongly predicts CHD in patients with T2DM.

Prognostic value of cardiac I-123 metaiodobenzylguanidine imaging in patients with non-insulin-dependent diabetes mellitus

BACKGROUND

123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy is a useful tool for diagnosing cardiac autonomic neuropathy (CAN) in non-insulin-dependent diabetes mellitus (NIDDM). However, the long-term prognostic value for cardiac events or mortality in NIDDM has not been clarified.

METHODS AND RESULTS

We investigated the long-term prognostic value of cardiac MIBG imaging for both cardiac event and mortality owing to a variety of causes of death in NIDDM. 144 NIDDM patients were analyzed retrospectively with the end-points of a cardiac event and various causes of mortality. The heart-to-mediastinum uptake ratio on the delayed image (H/M [d]) was obtained from anterior planar imaging. The mean follow-up period was 7.2+/-3.2 years. Seventeen patients had a cardiac event onset and 7 patients died during observation. During the same observation course, 16 patients died, including some who died of cardiac event. Both multivariate and univariate analyses revealed that decreased H/M (d) (<1.7) was the independent predictor of long-term mortality for a variety of causes of death. Although the value of H/M (d) was not a significant prognostic factor for predicting a cardiac event, CAN, diagnosed by a combination of H/M (d) and coefficient variance of RR interval, was an independent predictor for the cardiac event in NIDDM.

CONCLUSION

MIBG myocardial scintigraphy was useful for predicting cardiac events and long-term mortality in NIDDM.

The role of lipids in the development of diabetic microvascular complications: implications for therapy

Dyslipidemia is a major factor responsible for coronary heart disease and its reduction decreases coronary risk in patients with diabetes mellitus. However, the association of dyslipidemia with microvascular complications and the effect of intervention with lipid-lowering therapy in diabetes have been less investigated. We present the systematic review of association and intervention studies pertaining to dyslipidemia and microvascular disease in diabetes and also review possible mechanisms. Dyslipidemia may cause or exacerbate diabetic retinopathy and nephropathy by alterations in the coagulation-fibrinolytic system, changes in membrane permeability, damage to endothelial cells and increased atherosclerosis. Hyperlipidemia is associated with faster decline in glomerular filtration rate and progression of albuminuria and nephropathy. Recent evidence also suggests a role of lipoprotein(a) in progression of retinopathy and nephropathy in patients with diabetes mellitus. Lipid-lowering therapy, using single agents or a combination of drugs may significantly benefit diabetic retinopathy and diabetic nephropathy. In particular, hydroxymethyl glutaryl coenzyme A reductase inhibitors may be effective in preventing or retarding the progression of microvascular complications because of their powerful lipid-lowering effects and other additional mechanisms. However, most of the data are based on short-term studies, and need to be ascertained in long-term studies. Until more specific guidelines are available, aggressive management of diabetic dyslipidemia, according to currently accepted guidelines, should be continued for the prevention of macrovascular disease which would also benefit microvascular complications.